Today's mobile devices connect to networks using various radio technologies, such as Bluetooth, WiFi, GSM, and NFC. These devices typically detect availability of radio networks in the vicinity of the device by actively probing or scanning the environment. For example, devices that include WiFi functionality typically probe the environment for WiFi networks by broadcasting probe requests in the form of short radio signals (e.g., packets). These radio signals are received by receiving devices (e.g., WiFi access points) located in the vicinity, which can then respond to the requests by sending technical information (e.g., device specifications, service set identifier (“SSID”) of the network, etc.) to the mobile devices. An example of conventional communication between a mobile device and a WiFi access point in a WiFi network is illustrated in FIG. 1. As shown in FIG. 1, the device can additionally transmit an authorization request to the WiFi access point, which can respond with an authentication success message and subsequently establish a communication session with the device.
More information concerning WiFi radio signal packet types is set forth in Appendix A.
A typical probe request includes various information regarding the mobile device, including the mobile device's media access control (“MAC”) address (which is a unique string of letters and numbers that identifies the network interface of the mobile device), signal strength, and other non-personally identifiable information. Because a mobile device with WiFi functionality turned on or enabled will continually broadcast probe requests, these probe requests are increasingly being used as signals to track the presence and movement of users. That is, by simply using existing WiFi infrastructure or a custom WiFi sensor, probe requests (and the information contained therein) can be recorded and later processed for tracking purposes. Retail stores in shopping malls are now tracking their customers' movements by following the WiFi signals from their smartphones to study consumer behavior—Euclid Analytics provides a tracking system that measures signals between a smartphone and a WiFi antenna to count the number of people who walk by and enter a store; and RetailNext is another company involved in this space.
To prevent a mobile device from broadcasting probe requests, or any other radio signal that can enable remote capturing and tracking, a user can turn off or disable the corresponding radio communication functionality of their mobile device. Although this is a simple and easy way to prevent tracking, it does introduce productivity and usability issues. In terms of productivity, for example, the mobile device user may lose desired online connectivity and may be unable to access remote resources, such as web pages or e-mail if radio communication functionality of the mobile device is turned off. In terms of usability, the user must remember to turn the functionality off when not needed, and on again when needed, which in today's busy life, can be difficult.
Furthermore, the architecture of current mobile operating systems includes probe requests in their WiFi implementation, which cannot be easily blocked simply by running separate code or software. This leaves mobile device users with no option of preventing tracking other than by manually turning off the radio communication functionality entirely.